The present invention relates to a bumper for a motor vehicle.
The following discussion of related art is provided to assist the reader in understanding the advantages of the invention, and is not to be construed as an admission that this related art is prior art to this invention.
Bumpers are provided as standard equipment on both the front and the rear of motor vehicles to absorb the impact energy caused by minor impacts and to prevent or minimize damage to the actual structural support of the motor vehicle. A bumper typically includes a cross member which can be attached transversely to the side rails by way of crash boxes. The function of the cross member is to tranfer the energy resulting from an impact into the crash boxes, where the impact energy is converted into deformation energy. The system is here matched such that the crash boxes are located close to the center on the side rail of a motor vehicle, with the impact energy being transferred to the crash boxes and hence to the side rails via the cross member with minimal bending moment.
Various bumpers of different designs are known in the art. For example, U.S. Pat. No. 6,349,521 B1 discloses a bumper with a rigid hollow cross member. The cross-section of the cross member varies along its length so as to provide high energy absorption commensurate with the load.
EP 1 730 002 B1 discloses a bumper with a cross member having a U-shaped longitudinal profile that is closed off with a cover plate. EP 1 736 369 A2 also discloses a saucer-type cross member.
DE 102 06 011 A1 and DE 101 35 903 A1 disclose cross members provided with indentations in the attachment regions with the crash boxes, wherein the indentations engage in the open ends of the crash boxes. The intent is here to provide transverse stability to the cross member.
Bumpers must satisfy regulatory requirements as well as demands from consumer protection agencies aimed at protecting pedestrians. In addition, requirements from the classification tests of insurers (RCAR, GDV) must be satisfied. The automobile manufacturers typically also require optimal utilization of the installation space, ease of installation, high energy absorption capability and lowest possible weight as well as acceptable costs. In addition, the goal of reducing CO2-emission requires a consequent implementation of lightweight construction in vehicle design. However, the required weight reduction and the insurance classification tests tend to contradict one another.
It would therefore be desirable and advantageous to address this problem and to obviate other prior art shortcomings by providing a fully functional bumper which is lightweight and has an improved loading capacity.